This five-year longitudinal project will study the clinical presentation, outcomes, and predictors of outcomes of geriatric depression with a focus on the effect of age of illness onset. The hypothesis is that patients with first occurrence of depression in late life (LLD) differ from subjects have first occurrence of depression in early life (ELD) in the following ways: 1) more LLD subjects have delusion, medical morbidity, and/or cognitive dysfunction during episodes; 2) LLD subjects have poorer outcome, including more relapses, dementia, and medical morbidity; and 3) LLD subjects have different demographic, clinical, and psychosocial predictors for specific outcomes. This hypothesis is based on findings, including our preliminary data, which suggest that clinical, biological and family history differences exist between LLD and ELD. Three groups will be studied: 1) the LLD group (N = 65), which consists of subjects who first had depression between age 65 and 85 years; 2) the old- ELD group (N = 65), which will include subjects age-matched with the old ELD group and first experienced depression between age 20-64 years. After an extensive initial evaluation, the subjects will have a person-to-person assessment every six months and will also be contacted by telephone between person-to-person assessments. The study will use recently developed methods for longitudinal investigations (Longitudinal Interval Follow-Up Evaluation, LIFE, for assessment; Life Table Method for data analysis) which provide clinically relevant information such as outcome probabilities for individual patients. The study is expected to yield information that clinicians can use to: 1) determine prognosis of geriatric depression; 2) assess risk-benefit ratio of therapeutic or preventive interventions; 3) identify periods of highest risk for adverse outcomes, and plan treatment accordingly. We anticipate that findings from this study will stimulate clinical research testing new treatment and prevention models, and will comprise the background for studies seeking to identify subtypes of geriatric depression with different clinical and biological characteristics.